Chlorination of cresidine



UNITED STATES PATENT OFFICE '1,930,753 CHLORINATION or CRESIDINE Emeric Havasand Henry R. Lee, South Milwaukee, Wis, assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application January 25, 1932 Serial No. 588,819

11 Claims. (01. 260'130.5)

This invention relates to a process of chlorito form -chloro-2-formylamino-4-methyl-lnating cresidine (l-methoXy-2-amino-4-methylanisol; adding an aqueous hydrochloric acid sobenZ-ene) to produce 5-chloro-2-amino-4-methy1- lution and heating to hydrolyze off the formyl anisol. group; and recovering the precipitated hydro-l 5 It is an object of this invention to devise a chloride Of 5-chloro-2-amino-4-methyl-anisol. 60

simple, economical and efficient method for ob- Without limiting our invention to any particutaining 5-ch1oro-2-amino-4-methyl-anisol in a l r pr u the f ll win x mpl i iv n high t t of purity to illustrate our preferred method of operation.

Gther and further important objects of this Parts mentioned are parts y Weightinvention will become apparent from the following description and appended claims. a

Although 5-chloro-2-aininol-ine hyl-l-anisol Parts Of CrBSid-ine m th Xy2-amin0 constitutes a valuable intermediate for dyestuffs, 4-t0111fl1e) and 120 p s of 0% fo mic acid are no method for its direct preparation appears in heated to ether at about 100-103 C. for about the literature. This compound has apparentl 3 hours. The mass is then cooled to about 70 C. 0 heretofore been obtained merely as a by-product and 590 Parts Of toluene a e added. The mass is in the reduction of 2-nitro-4-methyl-anisol by the now heated di ill O f the eXCess of formic aid of tin and hydrochloric acid (Beilstein, 4th acid as Well as any Water t at is p s nt and Ed VOL X111, page 605) then cooled to about 50 C. Additional. toluene Example 65 We have new found that t Valuable t is now introduced into the mass to bring the di t may b prepared directly by chloronattotal quantity of toluene to about 1800 parts. ing' an N .a cj dy1 derivative of cresidine For best tQluene-dfluted mass is (3001661 to EJOOLlt 20 results we combine our novel discovery with the Chlorine gas is p sed into the miXture invention set forth in our copending application at C. until 142 parts have be n Consumed. Ser. No. 531,644, thereby accomplishing the departs of Water re now added and 170 parts sired result with a maximum degree of efiiciency of an aqueous hydrochloric d Solution (26 and economy In other Words, We found that f B.) are introduced. The mass is heated at about best results the forrnylamino derivative of cresifor about 2 hours, 000186 130 0 C- dine should be prepared and used as initial mateand d- The filter Cake tut s the 30 rial for our process, in preference to any other hydl'ochlonde of 5'Ch10T0-2-amin0'LmethOXyacidlyamino derivatives of cresidine. 4401119116 in high yield and 0f fi n purity In our copending application Ser No. 531,644 to be applicable directly for technical purposes. of which this isacontinuation in part, it has been The filtrate Consists of two phases: A Shown that if 1 m is CGnVer-ted into its aqueous phase containing dissolved therein the 35 N-formyl derivative, the latter may be u as excess hydrochloric acid and the hydrochloride initial material in a novel process of preparing of any isomeric chloro-cresldines formed, and 5-chloro-2-amino-l-toluene which process is (2) an Oily PhaSe from which the l n ma characterized by unusual simplicity of procedure, be recovered m Pure form by Steam dlstlllatw'fleconomy of materials, and general over-all effi- It Will thus be Seen that 0111 novel D is 40 ciency. The dominant characteristic of said dingly simple in operation, reduces the process consists of carrying out the chlorination handling of materials to a minimum, Saves hydr of the formylamino body and subsequent hy- O iC i p y a OOmDELMfiiVBIY Cheap drolysis of the formyl group in an organic mey t g a e a i e pensive solvent for dium immiscible with water, such as toluene. the reaction, and enables the recovery of the 45 We have now found that said process is apsame without Waste and'at very little cost.

plicable with equal advantage to the manufacture Also, the separation of 5-ch1oro-2-aminolof 5-chloro-2-amino-4-methyl-anisol. methyl-anisol from any isomers that may be Based on this discovery, therefore, our preformed during the reaction is substantially comferred process consists of reacting cresidine with plete, and the product is obtained in practically 50. formic acid, whereby to obtain 2-formylaminopure state, and in high yield.

l-methyl-anisol; dissolving the latter in an inert If desired, the various intermediate products organic solvent which is immiscible with water, formed in the reaction may be isolated. The for instance, toluene; partially evaporating to treatment of cresidine with formic acid in the remove residual moisture; treating the mass with first step of the above process results in Z-formyl- 55. a chlorinating agent such as gaseous chlorine aminoi-methyl-l-anisol. The chlorination of no this product according to the above process yields 5-chloro-2-formylamino-4 methyl anisol and some isomeric derivatives. 'Ihese chlorinated compounds may be isolated by neutralizing the reaction mass, and distilling off the toluene. The 5-chloro-compound may be separated from its isomers by recrystallizing from toluene. It is a white crystalline substance, melting at 91 C. When a toluene solution thereof is treated with aqueous hydrochloric acid solution, the formyl group splits off, and the resulting amino group is converted into the HCl salt, which is insoluble toluene, and therefore either dissolves in the aqueous phase or precipitates.

It will be understood that many variations and modifications are possible in the specific procedure disclosed, without departing from the spirit of this invention.

Thus, instead of chlorine gas, other ch1orinating agents which are adapted for use in anhydrous media may be used; for instance, sulfuryl chloride. Instead of toluene, any other organic solvent may .be used, provided it is a good solvent for formylcresidine, immiscible with water, and not readily chlorinated at low temperatures in the absence of a catalyst. Benzenoid solvents such as, for instance, benzene and chloro-benzene are specific examples of solvents that may be used in place of toluene.

Many other variations and modifications are possible in our procedure without departing from the spirit of this invention.

We claim: 7

1. The process of preparing a 5-chloro-2- amino-4-methyl-1-aniso1 compound which com,- prises chlorinating a cresidine in which the amino group is protected by an organic acidyl group.

2. In the process of manufacturing a chlorinated cresidine compound, the step which comprises chlorinating 2-formylamino--methylanisol.

3. In the process of manufacturing 5-chloro- 2-amino-4-methyl-l-anisol, the steps comprising chlorinating 2-formylamino-4-methyl-aniso1 and hydrolizing the product to, eliminate the formyl group.

4. As a new product, 5-chl'oro-2-formylamino- 4-methyl-l-anisol.

5. In the process of chlorinating cresidine, the steps comprising reacting cresidine with formic acid, chlorinating the reaction product formed and hyrdolyzing the resulting chlorinated product to eliminate the formyl group.

6. In the process of manufacturing chlorinated cresidine, the step which comprises effecting the chlorination of N-formyl cresidine in an organic liquid medium which is immiscible in water. 7. In the process of manufacturing chlorinated cresidine, the step which comprises reacting with a chlorinating agent, 2-formylamino4-methy1 anisol dissolved in. a benzenoid solvent.

8. In the process of manufacturing chlorinated cresidine, the step which comprises effecting the chlorination of 2-formylamino-4-methy1-anisol in a. medium of toluene.

9. In the process of preparing chlorinated cresidine, the step which comprises passing chlorine gas into a solution of N-formyl-cresidine in toluene.

10. A process of preparing a 5-chloro-2-amino- -methyl-anisol compound, which comprises passing chlorine gas into a solution of N-formylcresidine in toluene, adding an aqueous hydrochloric acid solution, warming the mass to eifect hydrolysis of the formyl group, and recovering the precipitated hydrochloride of 5-chloro-2- amino-4-methyl-anisol.

11. The process of preparing a 5-chloro-2- amino-l-methyl-anisol compound which comprises reacting upon cresidine with formic acid to produce N-formyl-cresidine, dissolving the latter in toluene, heating the mixture to eliminate excess formic acid and water, passing chlorine gas into the toluene solution of the N-formylcresidine, adding an aqueous hydrochloric acid solution, warming the mass to efiect hydrolysis of the formyl group, and filtering to isolate the hydrochloride of 5-chloro-2-amino-4methylanisol.

EMERIC HAVAS. HENRY R. LEE. 

